关于奥陶纪“茅坪组”

在上世纪 6 0年代 ,“茅坪组”这一名称先后被赋予两个完全不同的岩石地层单元 ,一个是奥陶纪的 ,命名地点在江西崇义 ,另一个是寒武纪的 ,命名地点在湖北咸丰。在后来的很长一段时间里 ,这一名称被各自使用 ,互不相干。近年来的关于中国地层的若干总结性和立典性文献或地层清理工作对该组名的采用了不同的看法 ,或取其一 ,或都不取 ,也未详加说明原因 ,有些混乱。奥陶纪的“茅坪组”由魏秀等 (1 96 6 ) 2命名 ,地点在崇义县茅坪 ,是一套以轻变质板岩为主的地层 ,含笔石 Anisograptus、Adelograptus和 Clono-graptus等 ,时代为早奥陶世 …

ABOUT THE ORDOVICIAN MAOPING FORMATION OF CHINA

The Maoping Formation was named respectively and used for two different and unrelated 1ithological units. In 1966 the name was proposed by Wei Xiu zhe and others to define a suite of slightly metamorphosed slates of Early Ordovician age in Chongyi, Souhern Jiangxi. However, in 1968 the same term was used by Hubei Geological Survey for a suite of dolomites of Middle Cambrian age in Xianfeng, West Hubei, probably without having knowledge of this Homonymum. Unfortunately this name has since been used for decades separately by Cambrian and Ordovician biostratigraphers causing serious confusion, which will be clarified and discussed herein. According to the priority rule, the later name is invalid and should not be used again, and it is here suggested that a new name should be given to the Cambrian rock unit concerned. Lithologically Maoping Formation is also shown to be different from Jueshangou Formation defined for the Jinggang Mts. to the north of Chongyi region, and from Yinchufu Formation in Western Zhejiang. Therefore the term is regarded as valid, restricted to southern Jiangxi. Up to date, quite abundant but poorly preserved graptolites have been discovered from the rocks, indicating an age of early Tremadoc to possibly earliest Arenig age (Early Ordovician).